linux-kernel - [PATCH] USB: Fix error handling in gadget driver

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Message-Id: <20251116014948.14093-1-make24@iscas.ac.cn>
Date: Sun, 16 Nov 2025 09:49:48 +0800
From: Ma Ke <make24@...as.ac.cn>
To: gregkh@...uxfoundation.org,
	vz@...ia.com,
	piotr.wojtaszczyk@...esys.com,
	make24@...as.ac.cn,
	arnd@...db.de,
	stigge@...com.de
Cc: linux-usb@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org,
	stable@...r.kernel.org
Subject: [PATCH] USB: Fix error handling in gadget driver

lpc32xx_udc_probe() acquires an i2c_client reference through
isp1301_get_client() but fails to release it in both error handling
paths and the normal removal path. This could result in a reference
count leak for the I2C device, preventing proper cleanup and
potentially leading to resource exhaustion. Add put_device() to
release the reference in the probe failure path and in the remove
function.

Calling path: isp1301_get_client() -> of_find_i2c_device_by_node() ->
i2c_find_device_by_fwnode(). As comments of
i2c_find_device_by_fwnode() says, 'The user must call
put_device(&client->dev) once done with the i2c client.'

Found by code review.

Cc: stable@...r.kernel.org
Fixes: 24a28e428351 ("USB: gadget driver for LPC32xx")
Signed-off-by: Ma Ke <make24@...as.ac.cn>
---
 drivers/usb/gadget/udc/lpc32xx_udc.c | 35 +++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/gadget/udc/lpc32xx_udc.c b/drivers/usb/gadget/udc/lpc32xx_udc.c
index 1a7d3c4f652f..b6fddfff712d 100644
--- a/drivers/usb/gadget/udc/lpc32xx_udc.c
+++ b/drivers/usb/gadget/udc/lpc32xx_udc.c
@@ -2986,6 +2986,7 @@ static int lpc32xx_udc_probe(struct platform_device *pdev)
 	int retval, i;
 	dma_addr_t dma_handle;
 	struct device_node *isp1301_node;
+	bool isp1301_acquired = false;
 
 	udc = devm_kmemdup(dev, &controller_template, sizeof(*udc), GFP_KERNEL);
 	if (!udc)
@@ -3013,6 +3014,7 @@ static int lpc32xx_udc_probe(struct platform_device *pdev)
 	if (!udc->isp1301_i2c_client) {
 		return -EPROBE_DEFER;
 	}
+	isp1301_acquired = true;
 
 	dev_info(udc->dev, "ISP1301 I2C device at address 0x%x\n",
 		 udc->isp1301_i2c_client->addr);
@@ -3020,7 +3022,7 @@ static int lpc32xx_udc_probe(struct platform_device *pdev)
 	pdev->dev.dma_mask = &lpc32xx_usbd_dmamask;
 	retval = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
 	if (retval)
-		return retval;
+		goto i2c_fail;
 
 	udc->board = &lpc32xx_usbddata;
 
@@ -3038,28 +3040,32 @@ static int lpc32xx_udc_probe(struct platform_device *pdev)
 	/* Get IRQs */
 	for (i = 0; i < 4; i++) {
 		udc->udp_irq[i] = platform_get_irq(pdev, i);
-		if (udc->udp_irq[i] < 0)
-			return udc->udp_irq[i];
+		if (udc->udp_irq[i] < 0) {
+			retval = udc->udp_irq[i];
+			goto i2c_fail;
+		}
 	}
 
 	udc->udp_baseaddr = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(udc->udp_baseaddr)) {
 		dev_err(udc->dev, "IO map failure\n");
-		return PTR_ERR(udc->udp_baseaddr);
+		retval = PTR_ERR(udc->udp_baseaddr);
+		goto i2c_fail;
 	}
 
 	/* Get USB device clock */
 	udc->usb_slv_clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(udc->usb_slv_clk)) {
 		dev_err(udc->dev, "failed to acquire USB device clock\n");
-		return PTR_ERR(udc->usb_slv_clk);
+		retval = PTR_ERR(udc->usb_slv_clk);
+		goto i2c_fail;
 	}
 
 	/* Enable USB device clock */
 	retval = clk_prepare_enable(udc->usb_slv_clk);
 	if (retval < 0) {
 		dev_err(udc->dev, "failed to start USB device clock\n");
-		return retval;
+		goto i2c_fail;
 	}
 
 	/* Setup deferred workqueue data */
@@ -3161,6 +3167,8 @@ static int lpc32xx_udc_probe(struct platform_device *pdev)
 	dma_free_coherent(&pdev->dev, UDCA_BUFF_SIZE,
 			  udc->udca_v_base, udc->udca_p_base);
 i2c_fail:
+	if (isp1301_acquired && udc->isp1301_i2c_client)
+		put_device(&udc->isp1301_i2c_client->dev);
 	clk_disable_unprepare(udc->usb_slv_clk);
 	dev_err(udc->dev, "%s probe failed, %d\n", driver_name, retval);
 
@@ -3170,6 +3178,18 @@ static int lpc32xx_udc_probe(struct platform_device *pdev)
 static void lpc32xx_udc_remove(struct platform_device *pdev)
 {
 	struct lpc32xx_udc *udc = platform_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+	struct device_node *isp1301_node;
+	bool isp1301_acquired = false;
+
+	/* Check if we acquired isp1301 via device tree */
+	if (dev->of_node) {
+		isp1301_node = of_parse_phandle(dev->of_node, "transceiver", 0);
+		if (isp1301_node) {
+			isp1301_acquired = true;
+			of_node_put(isp1301_node);
+		}
+	}
 
 	usb_del_gadget_udc(&udc->gadget);
 	if (udc->driver) {
@@ -3189,6 +3209,9 @@ static void lpc32xx_udc_remove(struct platform_device *pdev)
 	dma_free_coherent(&pdev->dev, UDCA_BUFF_SIZE,
 			  udc->udca_v_base, udc->udca_p_base);
 
+	if (isp1301_acquired && udc->isp1301_i2c_client)
+		put_device(&udc->isp1301_i2c_client->dev);
+
 	clk_disable_unprepare(udc->usb_slv_clk);
 }
 
-- 
2.17.1